4/4 Knotty Pine
A board of random width that is 1" thick and is of the species Knotty Pine.

6/4 thickness
A board that is 1-1/2 inches in thickness (before planing).

8/4
A board with a thickness of 2 inches in the rough would be described as a 8/4 (eight quarters) thick board.

Air Drying
A method of seasoning wood that allows covered stacks of cut lumber to dry naturally in open air.

Annual Ring
The rings that are generated each year as a tree grows. By counting the growth rings the age of the tree can be determined. The size of the rings can also indicate what type of growing season occurred during the year

Appearance Lumber
A variety of non-structural grades intended for applications where strength is not the primary consideration.

Ballast
Smooth AGGREGATE placed on the surface of the roof to weigh down the roofing. Also protects the roof materials from ultraviolet light.

Band Joist
Piece of lumber to which the ends of the JOISTS are nailed or screwed. A BAND JOIST is critical to the strength of the FLOOR SYSTEM because it holds the regular joist ends in their vertical position.

Base Shoe
Molding placed at the corner between the BASE MOLDING and floor. Usually used when a wood finish floor is installed.

Batt Insulation
Insulation made from matted fibers which may be left unfaced or may be faced on one or both sides with KRAFT PAPER, foil, or vinyl.

Beadboard
A board having a half-round profile milled into one edge.

Beaded Board
See Beadboard.

Beam Pocket
Notch or opening at the top of a BEARING WALL or supporting column which secures and bears the weight of a beam.

Bearing Wall
Any wall that supports a load above it, such as a ROOF SYSTEM or a FLOOR SYSTEM. A BEARING WALL is a STRUCTURAL PART.

bf
Symbol for Board Foot.

Bird Stop
Material used to fill the space under the first COURSE of tile at the EAVE line to prevent birds from nesting in the roofing.

Biscuit
Joint between two boards made by using a BISCUIT SAW to notch out the ends of the joined boards. A premanufactured BISCUIT fits into the slots made by the BISCUIT SAW. The glued BISCUIT swells as the glue soaks in, forming a very tight fit when the joint dries.

Blind Nailing
To drive a nail into a part of the board that will not be visible on the finished product. See also: FACE NAILING.

Board Foot
A board foot is a unit of quantity equal in volume to a board 12 inches long x 12 inches wide x 1 inch thick.

Bole
The lower section of a trunk of a tree from the ground to the first limb or branch.

Bottom Chord
The lowermost horizontal member of a truss.

Bow
Longitudinal distortion of lumber from a true plane, from end to end.

Bowstring Truss
TRUSS with a curved TOP CHORD and horizontal BOTTOM CHORD so that the top looks like a bow string and the bottom looks like a bow.

Brad Nail
A slender wire nail with a small barrel-shaped head.

Burl
A wart-like growth or bump on the trunk of a tree that when cut into veneer produces a spectacle pattern. Burled walnut, maple, and rosewood veneers are especially prized by woodworkers.

Buttress
The broad base of a tree trunk that provides the strength for a tree to support its own weight.

Camber
The curvature built into a beam (in a direction opposite to the expected deflection) to prevent it from appearing to sag under a loaded condition.

Cantilever
The portion of a structural beam which extends or "cantilevers" beyond the end support, and whose end is not supported.

CDX
Structural panel grades are generally identified in terms of the veneer grade used on the face and back of the panel. The minimum grade of veneer permitted in exterior plywood is C-grade. D-grade veneer is used in panels intended for interior use or applications protected from permanent exposure to weather such as roofing and sub-floors. CD plywood with exterior glue not intended for long-term exterior use must be covered.

Chair Rail
A molding installed on a wall at a height that will protect the wall from damage due to the backs of chairs coming in contact with it. In modern times used more for decoration than for function.

Checks
Lengthwise splits in wood which may occur as wood is dried or seasoned. Typically occurs across the rings of annual growth.

Chlorotic
A diseased condition of green plants marked by yellowing or blanching.

Conifer
Conifer species are trees or shrubs of the evergreen variety that bear cones. An example would be the pine.

Coniferous Forest
Forests comprised of mostly cone-bearing trees such as pine forests.

Core
The center layer of plies, particles or wooden strips in a manmade board.

Cripple Rafter
RAFTER that runs from a HIP RAFTER to a VALLEY RAFTER. A CRIPPLE RAFTER never reaches the wall TOP PLATE or the RIDGE BOARD.

Cripples
Short STUDS that are used to fill the gap under the WINDOW SILL and between the HEADER and the top PLATE if there is a gap. Also used in a NONBEARING WALL to fill the space above the door opening and the top PLATE when no HEADER is required.

Crosscutting
Sawing across the grain of a piece of wood.

Crowning
Arranging all framing members so that all crowns are in the same direction. See CROWNED STUD.

Dead Load
Permanent load consisting of all building parts and built-in fixtures that will be supported by a STRUCTURAL PART.

Deciduous
Trees are classified as deciduous if they shed their leaves annually. Typically these trees are of the hardwood variety; however, some softwood varieties also drop their needles annually.

Deflection
Downward vertical displacement due to a load.

Design Span
Span used to calculate the strength and deflection of a member usually measured from center to center of the bearing surface at each support.

Dimension Lumber
Lumber that is sawn and planed to standard sizes and lengths 2x4 through 2x12 inches across the grain by 8 to 24 feet in length. Most often used in construction.

Dimensional Lumber
General term for framing lumber. Examples would be 2x4, 2x6, 2x8, etc.

Dressed Lumber
Wood which has one or more planed surfaces.

Drying In
The process of making new construction weather-tight.

Drywall
Interior wall finish using mostly non-flammable materials. While DRYWALL actually refers to any interior finish made from plaster or gypsum board, in common usage it usually refers to a finish made from gypsum board.

Earlywood

The early part of a growth ring, consisting of pale inner wood with thin walls, formed in the spring and early summer. Also known as springwood.

Eight Quarters
The thickness of a board "in the rough" is defined in quarter inches. Four quarters (4/4) is actually 1 inch thick. Five quarters (5/4) is 1-1/4 inch thick, etc. Therefore, an eight quarters (8/4) board thickness would equate to 2-inches thick before planing.

End Grain
The surface of wood exposed after cutting across the fibers. The early part of a growth ring, consisting of pale inner wood with thin walls, formed in the spring and early summer. Also known as springwood.

Engineered Wood
Lamination technology allows the bonding or glueing of individual, thin sections of wood together to form long, straight lengths of lumber commonly called engineered wood products. Floor joists, beams and timbers are manufactured from smaller trees often from species once considered undesirable for building. This engineered process delivers quality and outstanding performance while also making more efficient use of our wood resources.

Fascia
Exterior horizontal trim piece that covers the vertical edge of the RAFTER TAILS. It can also be called the finish FASCIA because it is installed over the ROUGH FASCIA.

Fascia
Horizontal board covering the joint between the top of a wall and the projecting eaves.

Fiber and Cement Shingle
SHINGLE made from a combination of wood fiber and Portland CEMENT. FIBER and CEMENT SHINGLES can be made to resemble SLATE, tile, or wood.

Finger Joint
Joint which uses small tapered projections (fingers) which interlace to join two pieces of material.

Finger-Jointed
A process of joining shorter, defect-free lengths of stock together to form longer lengths. A series of "fingers" are milled into each end of the sections, which are then glued to each other to form the length. The "fingers" create a larger glueing surface than would exist if the stock were butted together. This increased glueing surface creates a joint that is actually stronger than the surrounding wood itself.

Fire Blocking
Piece of material installed to block the spread of fire from one side of it into wood framing members on the other side. The fire is forced to burn through the FIRE BLOCKING before it can reach another part of the framing system.

Fire Wall
Wall which has been designed to resist the spread of fire. FIRE WALLS in homes are typically required between the garage and living space. FIRE WALLS are usually rated by the hours they are designed to resist the spread of fire. A typical residential fire wall rating is one hour.

Flitch
A large piece of lumber cut out of a log that is then sawn into boards or VENEER strips.

Flitch Beam
A structural beam comprised of layers of laminate to form a wider, more solid beam.

Floor Truss
May be used instead of regular JOISTS or I-JOISTS, FLOOR TRUSSES are generally placed on wider centers, are deeper and more expensive than other JOISTS. FLOOR TRUSSES are designed to allow plumbing, electrical, and heating runs to be placed inside of them instead of below them like is often required in other JOISTS.

Fly Rafter
GABLE RAFTER which is located under the OVERHANG part of the roof SHEATHING on the gable end. It is not directly supported by the exterior wall. Also sometimes referred to as the barge RAFTER or barge board.

Footing
Base upon which the structure will stand, it rests on the soil. A FOOTING ultimately supports all of the weight of the structure, it is a STRUCTURAL PART.

Framing Lumber
Includes the grades intended for structural applications in both conventional and pre-engineered framing systems.

Frieze Board
Horizontal trim piece installed at the top of the exterior wall, covering the joint between the SOFFIT and the exterior wall. The FRIEZE BOARD is often ornately decorated.

Furring Strip
Also called furr strips, they are often used on the interior of BLOCK or CONCRETE walls. FURRING STRIPS can be made from either metal or wood. They are fastened to the walls, ceiling, or floor system generally for the purspose of providing a surface to which the ceiling or wall covering may be easily attached.

Gable End Truss
TRUSS used at the ends of a GABLE ROOF, it as vertical members which are spaced to allow convenient attachment of the exterior wall SHEATHING.

Gambrel Roof
TRUSS used at the ends of a GABLE ROOF, it has vertical members which are spaced to allow convenient attachment of the exterior wall SHEATHING.

Girder
Large horizontal beam which may be used to provide structural support at specific BEARING POINTS along its length. A GIRDER is held up in position by columns or a BEARING WALL.

Glue Lam Beam
Short for glue-laminated beam, it is made of several layers of dimensional lumber glued together so that the joints in each layer are overlapped by other layers to provide strength. If the glue-lam beam has a CAMBER, it should be installed with the CAMBER up.

Glulam
Structureal glued laminated timber. An engineered (manmade) timber, used as load-carrying structural framing for roofs and other structural portions of building. Refers to products made by bonding suitably selected and prepared wood laminations with adhesives.

Hard Board
See "HARDBOARD"

Hardboard
Generic term for a panel manufactured primarily from wood fibers which are pressed together under heat and pressure in a large press. Typically used as underlayment for floor coverings.

Header
A beam used to support walls and/or floor and foot joists that run perpendicular to it.

Heartwood
The mature wood that forms the spine of a tree.

Heel
Point on a truss at which the top and bottom chords intersect.

Industrial Lumber
Includes both structural and non-structural grades that are intended for specific applications. Mining timbers, scaffold planks, foundation lumber and stress-related boards.

Jamb
The vertical member at the side of a window or door frame. Also refers to the horizontal member at the top of the window or door frame, as in head jamb, window jamb and door jamb.

Joist
Parallel, horizontal framing members that support floor or ceiling loads. JOISTS may be made from wood, steel, or concrete.

Laminated Veneer Lumber (LVL)
Structural grade timber veneers glued together under pressure to form a dimensionally stable and uniform product. An engineered wood product that is a substitute for dimensional lumber.

Latewood
That part of a tree's annual growth ring that is laid down in the latter part of the growing season.

Lumber Grade
A system by which lumber is ranked by strength or appearance.

Machine Stress
Lumber that has been mechanically stress-graded to measure stiffness of the material. Determines the strength of a piece of wood. Engineers specify certain strength requirements when they design buildings. Machine stressed lumber has been tested to certify that the wood meets the strength requirements.

Medium Density Fiberboard (MDF)
A composite panel made from wood fibers combined with synthetic resin or other suitable binder, bonded under heat and pressure.

Micro-Lam
Engineered lumber made up of thin layers of wood. Micro-lam is used as a structural material for joists, headers, beams, etc.

MSR
Machine Stress Rated framing lumber engineered to perform under pre-defined stress conditions.

Oriented Strand Board (OSB)
Structural, multi-layer panel of compressed strands (narrow wafers) bonded with a resin under heat and pressure in a press. Strands are oriented for strength in the core and face layers.

OSB
See "Oriented Strand Board"

Paralam
Engineered beam composed of thin strips of wood laminated together to form a structural framing member. Used for header beams and the like.

Particleboard
Panel manufactured from wood particles bonded together with synthetic resins under heat and pressure.

Plain Sawn
A term used to describe how a piece of wood has been sawn. The log is cut with growth rings that meet the faces of the board at angles of less than 45 degrees.

Plumb
Exactly vertical or true.

Plywood
Plywood is produced from thin sheets of wood veneer or plies, arranged in layers, oriented perpendicular to adjacent layers. Plywood always has an odd number of layers, each consisting of one or more plies. Sometimes a layer consists of two or more plies with the grain running in the same direction. The grain of the face and back layers typically runs parallel to the long dimension of the panel. Arranging the plies perpendicular to each other is called cross-lamination and it gives the panel strength in both directions because the greatest strength of wood is with the grain. The finished plywood panel is produced by bonding the plies under heat and pressure using adhesives. The adhesive produces a structural bond between the plies that is as strong or stronger than the wood itself. For more information, check out the APA at www.apawood.org.

Quarter Sawn
A term used to describe a piece of wood that has been cut from a log with growth rings between 60 and 90 degrees to the faces of the board.

Rafter
Sloped roof framing member that supports the roof SHEATHING as well as LIVE and DEAD LOADS that are placed on the roof.

Rip Cut
Sawing parallel to the grain.

Rotary Cut
A term used to describe a continuous sheet of veneer peeled from a log by turning it against a stationary knife.

Running Foot
Basically the same as "Lineal Foot." A running foot is the equivalent of a 12-inch length of material regardless of width.

S4S
S4S stands for "Surfaced 4 Sides." This term refers to a baord that has been milled on all four faces so that opposing faces are parallel to each other.

Soffit
Horizontal member that fills the gap between the exterior wall and the FASCIA.

SPF Stud
Spruce-Pine-Fir is a commercial softwood grade of 2x4 used for framing. Available in lengths from 8 to 10 feet.

Steam Bending
The process of "bending" or shaping boards into curved pieces by exposing them to steam. The steam softens the fibers and allows the wood to be shaped using preformed templates and clamps. Common in rocking chair construction.

Truss
An engineered building component made up of dimensional lumber formed into a rigid unit. Trusses are used in roofing to form rafters and ceiling joists. Trusses are also used in creating floor joists.

Waferboard
Structural panels of compressed wafers bonded with resin under heat and pressure in a press. The wafers, or flakes, are either randomly or directionally oriented.

Wane
A defect in lumber characterized by bark or a lack of wood at a corner or ledge.

Woodwright
Someone who works with wood, usually a craftsman.